This section provides background information related to the present disclosure which is not necessarily prior art.
Currently, lay down lip seals offering low power consumption due to low friction are recommended for use in engines with relatively low levels of crankcase pressure. The seal's radial force is sufficient to keep the lip in contact with a shaft for desired sealing performance yet is low enough to cause minimum friction. However, in certain forced induction engines such as turbocharged and supercharged engines, the crankcase pressure becomes negative and exceeds the capacity of the lay down lip seal to remain in contact with the shaft. This leads to the generation of an air flow from the environment to the crankcase. Interaction of this air flow with the sealing lip, oil and the shaft produces noise/squeal which is unacceptable to customers. Accordingly, it is desirable to provide a low friction seal that maintains seal contact in response to negative pressures on the oil side of the seal.